Iodine-containing contrast medium is a chemical used in iodine perfusion studies to enhance images taken during body scans such as X-rays and computed tomography (CT) scans. Increasingly, dual-energy computed tomography (DECT) scanners are being used to produce iodine perfusion maps of the body. These maps are useful in the diagnosis and detection of abnormal processes that may be related to a disease.
What is an iodine contrast media?
A contrast media is a chemical substance introduced into the body prior to a diagnostic scan. The most common type of contrast media is an iodine-containing contrast medium (ICCM), which can be administered through a small needle into a vein or in some cases, an oral solution.
When injected into the blood, contrast media moves into the stomach, bowel, blood vessels, and even in the cerebrospinal fluid. This can be observed through X-ray images and can be useful for understanding whether there are any blockages or abnormalities in the blood vessels supplying an organ.
What are the applications of iodine contrast media?
An iodine-containing contrast medium helps doctors give a definite diagnosis from a routine medical scan. This allows the treating physician to start an early and more accurate treatment plan.
Common diagnostic tests that use contrast media include angiograms and angiography, which are tests used to show images of blood vessels, as well as arthrography, which shows the inside of a joint, and myelography, a test used to visualize cerebrospinal fluid.
What are the side effects and contraindications of iodine contrast media?
Contrast medium is generally safe for use in humans, however, some patients may experience side effects, including hives, rash, or itching. Gastrointestinal side effects include nausea, vomiting, or diarrhea. Other side effects are general dizziness, fever, or headache.
It’s important to report any allergic symptoms that arise after the administration of a contrast medium to prevent harmful adverse effects. In some patients, contrast medium is not recommended, such as those with a history of asthma, cystic fibrosis, pregnancy, dehydration, kidney diseases, an intestinal blockage or any perforation.
Mapping iodine perfusion in the body
Increasingly, iodine maps created utilizing dual-energy computed tomography (DECT) scanners are used to help in image interpretation to diagnose a disease. Iodine perfusion maps have been utilized in the diagnosis of a multitude of diseases.
Usually, mapping of iodine perfusion via a DECT is used in patients who are suspected to have a pulmonary embolism. Pulmonary embolism (PE) is a potentially life-threatening disorder. In fact, PE is the most common acute cardiovascular disease, after a heart attack (myocardial infarction) or stroke.
When pulmonary embolism is detected early and properly, treatment can be successful, and the associated mortality can be reduced. Two of the most useful diagnostic tests are DECT and CT angiography. Thanks to the emergence of DECT, doctors can now get iodine perfusion maps of the lungs, which can allow them to detect and evaluate perfusion changes. It can lead to a better pulmonary CT angiography, detecting the presence of pulmonary embolism.
Many physicians and experts suggested that DECT can be a potential surrogate for perfusion computed tomography (CT). But, it has never been compared directly with perfusion CT in humans. Iodine maps created using DECT scanners are used to help in image interpretation of Computed Tomographic Pulmonary Angiography (CTPA) studies.
Iodine mapping can also be used in other diseases such as cancer and bowel disease. For instance, in one study by scientists in Boston, they found that DECT and iodine perfusion mapping have been useful in evaluating bowel disease among patients. DECT and iodine mapping can qualitatively improve the conspicuity of diseased bowel using iodine-selective images. Also, iodine maps help in evaluating gastrointestinal bleeding.